The Fluid Dynamics of the Bivalve Molluscs, Mya and Margaritifera

1966 ◽  
Vol 45 (2) ◽  
pp. 369-382
Author(s):  
E. R. TRUEMAN
Keyword(s):  
Fluid Dynamics ◽  
High Pressures ◽  
Mantle Cavity ◽  
The Body ◽  
Mya Arenaria ◽  
Bivalve Molluscs ◽  
Muscle System ◽  
Close Interaction ◽  
Antagonistic Muscle ◽  
Pressure Changes

1. A comparison is made of the fluid dynamics of a shallow, yet actively, burrowing bivalve, Margaritifera, with the sessile, deeply buried Mya arenaria. 2. In both adduction produces high pressures (up to ioo cm.) in the mantle and the pericardial cavities which are utilized in Margaritifera for locomotory purposes, in Mya principally for siphonal extension. 3. With siphonal and pedal apertures closed the mantle cavity of Mya is virtually watertight and acts, together with the blood, as the fluid of an antagonistic muscle system, whereby adduction causes siphonal extension and siphonal retraction produces an increase in gape of the valves. The close interaction between these two muscle systems is illustrated by pressure recordings of Mya in the normal buried position. 4. Siphonal movements are shown to be associated with divarication of the valves and accompanying pressure changes. 5. Consideration is given to the haemodynamics of Mya and by contrast with the high pressures involved in locomotion or siphonal movement, maximum pressures of only 2.5 cm. were recorded from the heart, producing a sluggish circulation. The higher pressures derived from the body musculature make an important contribution to movements of the blood.

The dynamics of burrowing in Ensis (Bivalvia)

1967 ◽  
Vol 166 (1005) ◽  
pp. 459-476 ◽  
Keyword(s):  
High Pressures ◽  
Mantle Cavity ◽  
The Body ◽  
Muscle System ◽  
Opening And Closing ◽  
Low Pressures

The digging activity of Ensis arcuatus shows six stages, together termed the 'digging cycle' which are repeated cyclically and are similar to those of other burrowing bivalves. A digging cycle involves the integration of pedal protraction and retraction with the opening and closing of the valves, much of the musculature of the body playing a part in each cycle. Extension and probing of the foot involves only the intrinsic pedal musculature which generates low pressures (10 cm) in the pedal haemocoele. The hinged shell acts as the basis of a fluid/muscle system which allows the strength of adduction to be used in digging and consists of two separate fluid filled chambers, the haemocoele and the mantle cavity. Adduction of the valves generates high pressures (100 cm) in each equally and simultaneously. In the haemocoele this pressure gives rise to the characteristic bulbous form of the foot which ensures a secure anchorage so that at pedal retraction the shell is drawn down. In the mantle cavity the pressure produces powerful jets of water which assist movement of the shell by loosening the adjacent sand. Estimates of the muscle tensions indicate that the pressures recorded may be obtained at tensions of not more than 2 Kg/cm 2 .

The Circulatory Physiology of Helix Pomatia

1973 ◽  
Vol 59 (2) ◽  
pp. 291-303
Author(s):  
BARBARA A. SOMMERVILLE
Keyword(s):  
Blood Flow ◽  
Helix Pomatia ◽  
Circulatory System ◽  
Mantle Cavity ◽  
Heart Beat ◽  
The Body ◽  
Pericardial Cavity ◽  
Circulatory Physiology ◽  
Pressure Changes ◽  
Characteristic Pressure

1. The pressure changes in the mantle cavity and various parts of the circulatory system of Helix pomatia have been measured. 2. There are characteristic pressure changes associated with the breathing movements, the pattern depending upon the point at which the measurement was made and, in the case of the heart, the position of the body at the time of recording. These pressure changes fail mainly within the range 2-8 cm H2O. 3. The pressure changes associated with contraction of the heart chambers fall within the range 1-2 cm H2O in pulmonary vein and auricle, 10-32 cm H2O in the ventricle, 1-3 cm H2O in the aorta and 1-8 cm H2O in the pericardial cavity. 4. An increased frequency and amplitude of heart beat was associated with an increased rate of blood flow.

The Hydraulic System of Urechis Caupo Fisher & Macginitie

1968 ◽  
Vol 49 (3) ◽  
pp. 657-667
Author(s):  
G. CHAPMAN
Keyword(s):  
Hydraulic System ◽  
Body Wall ◽  
High Pressures ◽  
Circular Muscle ◽  
Muscle Layer ◽  
The Body ◽  
Muscle System ◽  
Urechis Caupo ◽  
Hind Gut ◽  
Whole Muscle

1. The hydrostatic pressures recorded in the coelom of Urechis during peristalsis, irrigation, burrowing and hind-gut ventilation have been recorded continuously. The main muscular activities except burrowing take place at pressures of a few centimetres of water and, it is suggested, are mainly carried out by the outer circular muscle layer. The high pressures involved in burrowing demand the recruitment of the whole muscle system. 2. The hind-gut ventilation stops when internal pressure is raised, although changes in the contained volume of the body wall do not appear to provide information leading to the maintenance of a fixed volume. Instead this control is probably excercised by the hind gut. 3. An attempt is made to calculate the energy requirements of irrigation and ventilation and it is shown that these are small compared with the respiratory rate, indicating that the movement of large volumes of water for feeding purposes is not an extravagant way of obtaining food in terms of energy expenditure.

scholarly journals Rates of nitrogen excretion by species of Mytilus (Bivalvia: Mollusca)

1977 ◽  
Vol 57 (2) ◽  
pp. 355-369 ◽  
Author(s):  
B. L. Bayne ◽  
C. Scullard
Keyword(s):  
Volume Regulation ◽  
Excretion Rate ◽  
The Body ◽  
Mya Arenaria ◽  
Nitrogen Excretion ◽  
Mytilus Californianus ◽  
Marine Bivalve ◽  
Bivalve Molluscs ◽  
End Products ◽  
Animal Size

Although the nitrogenous excretory products of a number of marine bivalve molluscs have been identified (Hammen, Miller & Geer, 1966; Hammen, 1968; Emerson, 1969; Allen & Garrett, 1971; Bayne, 1973 a) and average values for rates of nitrogen excretion recorded for some species (Lum & Hammen, 1964; Hammen et al. 1966; Bayne, 1973a), there is little information available on the ways in which environmental factors may affect either the balance between the various nitrogenous end-products, or their rates of excretion. The most thorough investigations have dealt with the effects of reduced salinity, which causes an increase in the rates of excretion of ammonia by Macoma inconspicua (Emerson, 1969), Mya arenaria (Allen & Garrett, 1971) and Mytilus edulis (Bayne, 1975). Dilution of the medium is also known to accelerate the loss of amino acids from the body, as part of the mechanism of volume regulation (Pierce & Greenberg, 1972, 1973). There is some evidence of altered rates of excretion during starvation (Hammen, 1968; Emerson, 1969; Bayne, 1973 a, b) and differences in excretion rate due to differences in animal size have been documented for Donax vittatus by Ansell & Sivadas (1973) and for Mytilus californianus by Bayne, Bayne, Carefoot & Thompson (1976 a, b).

Endeolophos skeneae sp. nov. (Chromadoridae)—a free-living marine nematode epibiotically associated with deep-sea gastropod Skenea profunda (Skeneidae)

2010 ◽  
Vol 91 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Oleksandr Holovachov ◽  
Sven Boström ◽  
Nicole Reid ◽  
Anders Warén ◽  
Christoffer Schander
Keyword(s):  
New Species ◽  
Dreissena Polymorpha ◽  
Mantle Cavity ◽  
The Body ◽  
Marine Nematode ◽  
Bivalve Molluscs ◽  
Free Living ◽  
Long Tail ◽  
Symbiotic Associations ◽  
A New Species

A new species, Endeolophus skeneae sp. nov., epibiotically associated with the gastropod Skenea profunda, is described from light microscope and scanning electron microscope observations. The new species is characterized by homogeneous ornamentation of the cuticle with annules with very fine and numerous longitudinal ridges, equally distributed around the body, subcuticular discontinuity in cuticle pattern along the lateral sectors of the body, relatively long body (1.1–1.6 mm) and relatively long tail (141–188 μm, c' = 7.5–11.4), short (19–22 μm) L-shaped spicules with ventrally bent blade and simple plate-like gubernaculum without apophysis. Symbiotic associations between aquatic nematodes and molluscs are discussed, with special emphasis on Dreissena polymorpha, zebra mussels. It is suggested that nematodes find food and shelter in the mantle cavity of the bivalve molluscs, and in the umbilicus and aperture of the gastropods, but to reveal the exact mechanisms of symbiotic associations of nematodes with aquatic molluscs requires further research.

The rôle of the body fluid in the movement of soft-bodied invertebrates - II. The extenstion of the siphons of Mya arenaria L. and Scrobicularia plana (da Costa)

1956 ◽  
Vol 145 (921) ◽  
pp. 564-580 ◽  
Keyword(s):  
Body Fluid ◽  
Mantle Cavity ◽  
Constant Volume ◽  
The Body ◽  
Mya Arenaria ◽  
Muscle Fibres ◽  
Adductor Muscles ◽  
Scrobicularia Plana ◽  
Radial Muscle

It is widely held that molluscan organs are protruded and extended by a forceful influx of blood, but observations and experiments on Mya and Scrobicularia show that this is certainly not true for the movements of the siphons of these two lamellibranchs. The siphons of Mya are extended by water being forced into them from the mantle cavity by the action of the adductor muscles of the shell. Changes in length and shape of the siphons of Scrobicularia are effected solely by an intrinsic mechanism consisting of longitudinal and radial muscle fibres together with beds of collagen. The muscles are antagonized through the blood contained within the siphonal walls which at all times retain a constant volume.

scholarly journals Decompression sickness risk in rats by microbial removal of dissolved gas

1998 ◽  
Vol 275 (3) ◽  
pp. R677-R682 ◽  
Author(s):  
Susan R. Kayar ◽  
Terry L. Miller ◽  
Meyer J. Wolin ◽  
Eugenia O. Aukhert ◽  
Milton J. Axley ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
High Pressures ◽  
Decompression Sickness ◽  
Body Burden ◽  
The Body ◽  
Dissolved Gas ◽  
Hyperbaric Chamber ◽  
Methanobrevibacter Smithii ◽  
Water Rate ◽  
Microbial Removal

We present a method for reducing the risk of decompression sickness (DCS) in rats exposed to high pressures of H2. Suspensions of the human colonic microbe Methanobrevibacter smithii were introduced via a colonic cannula into the large intestines of the rats. While the rats breathed H2in a hyperbaric chamber, the microbe metabolized some of the H2diffusing into the intestine, converting H2and CO2to methane and water. Rate of release of methane from the rats, which was monitored by gas chromatography, varied with chamber H2pressure. This rate was higher during decompression than during compression, suggesting that during decompression the microbe was metabolizing H2stored in the rats’ tissues. Rats treated with M. smithii had a 25% (5 of 20) incidence of DCS, which was significantly lower ( P < 0.01) than the 56% (28 of 50) incidence of untreated controls, brought on by a standardized compression and decompression sequence. Thus using a microbe in the intestine to remove an estimated 5% of the body burden of H2reduced DCS risk by more than one-half. This method of biochemical decompression may potentially facilitate human diving.

Changes in Blood Pressure, Heart Rate and Breathing Rate During Moderate Swimming Activity in Rainbow Trout

1967 ◽  
Vol 46 (2) ◽  
pp. 307-315 ◽  
Author(s):  
E. DON STEVENS ◽  
D. J. RANDALL
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Rainbow Trout ◽  
Venous Blood ◽  
The Body ◽  
Swimming Activity ◽  
Breathing Rate ◽  
Blood Pressures ◽  
Ventral Aorta ◽  
Pressure Changes

1. Changes in blood pressure in the dorsal aorta, ventral aorta and subintestinal vein, as well as changes in heart rate and breathing rate during moderate swimming activity in the rainbow trout are reported. 2. Blood pressures both afferent and efferent to the gills increased during swimming and then returned to normal levels within 30 min. after exercise. 3. Venous blood pressure was characterized by periodic increases during swimming. The pressure changes were not in phase with the body movements. 4. Although total venous return to the heart increased during swimming, a decreased blood flow was recorded in the subintestinal vein. 5. Heart rate and breathing rate increased during swimming and then decreased when swimming ceased. 6. Some possible mechanisms regulating heart and breathing rates are discussed.

Analysis on Additional Pressure of Tube Sidewall of Immersed Tube Tunnel in Sinking Process of Tube Segment

2013 ◽  
Vol 387 ◽  
pp. 180-184
Author(s):  
Ya Dong Li ◽  
Hai Hong Mo ◽  
Jun Shen Chen
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Simulation Analysis ◽  
Lateral Wall ◽  
Special Position ◽  
Additional Pressure ◽  
Whole Process ◽  
Pressure Changes ◽  
Dynamics Method ◽  
Tube Segment

The numerical simulation analysis on the whole process of the tube immersing is researched, which use computational fluid dynamics method, is based on RNG k~ε turbulence model. The analysis shows that: additional pressure of tube lateral wall depends on the changed flow field cause by tube immersing; through the analysis, it have explored the special position of additional pressure changes in the process of immersing; it also shows some problems should be paid attention, through analysis the stress of special position.

scholarly journals Analysis of Stress and Strain to Determine the Pressure Changes in Tight-Fitting Garment

2020 ◽  
Vol 20 (1) ◽  
pp. 49-55
Author(s):  
Nareerut Jariyapunya ◽  
Blažena Musilová
Keyword(s):  
Mechanical Properties ◽  
Mathematical Models ◽  
Initial Phase ◽  
Circumferential Stress ◽  
The Body ◽  
Stress And Strain ◽  
Laplace’S Law ◽  
Pressure Changes ◽  
The Relationship ◽  
Laplace's Law

AbstractBased on the mechanical properties of stretch fabrics and Laplace’s law, the mathematical models have been developed enabling one to determine the values of the relationship between the fabric strain and the circumferential stress depending on pressure and diameter of the body. The results obtained refer to the values of the parameters assessed for the initial phase of their exploitation, which allow us to preliminarily predict the values of these parameters.

Sign in / Sign up

Export Citation Format

Share Document